This invention relates to a novel process for the preparation of starch esters. More particularly, the present invention relates to the preparation of such esters by reacting starch under controlled conditions with a selected N,N'-disubstituted imidazolium salt.
The modification of starch by chemical derivatization and in particular the preparation of starch esters is well known in the art. An excellent review of the preparation of starch esters up to 1968 may be found in Starch and Its Derivatives, Chapter 12, J. A. Radley, Chapman and Hall, Ltd. The preparation of starch esters utilizing reactions of starch with imidazolides of carboxylic or sulfonic acids, is described in U.S. Pat. No. 3,720,663 issued Mar. 13, 1973 reissued as U.S. Pat. No. Re. 28,809. However, the prior art does not teach the preparation of starch esters or other starch derivatives using the reagent compounds of the present invention.